Amplifier power

mangata572
mangata572 Posts: 52
edited February 2003 in Electronics
I am thinking about up-grading to separates some day. Starting with amps first, using my h/k 320 as a pre/pro first, then changing to a real pre/pro later. Polk recommended amplifier power for my speakers is (all 8 ohm) as follows. RTi150; 50-500, CSi40; 10-150, FXi50; 10-150, RTi38; 20-150. The h/k receiver is rated at 55 w/channel and is never turned up past 0db (-80db to +10db manual warns not going above 0db) and that is plenty loud for me.

I have a few questions. Let’s say I’m looking at a 225 w/channel into 8ohm x 7 amp. Would I run the risk of blowing the lower rated speakers in my set-up, even if it is not turned up to very high volumes? Would I gain great benefits with separates, or should I get a flagship receiver instead (like the Sunfire Ultimate receiver [200 w/channel x 7] or is this still too much power)? What about bi-amping the 150s? Would they play twice as loud as the rest, or can you compensate using the channel volume settings? Please help with these crazy thoughts!
Post edited by mangata572 on

Comments

  • HBombToo
    HBombToo Posts: 5,256
    edited February 2003
    Very good questions first off.

    Your h/k 320 is a very good unit and the thought of using it as a pre/pro will allow extra cash for some higher end seperates.

    For instance I have an h/k 520 and use it as a pre/pro into my Outlaw 770 7X200W into 8 Ohms. The h/k offers all the dsp's I care to use and more but again this is a personel decision.

    As far as blowing your speakers because you have a more powerfull amp is a misinterpretation of what is actually taking place. In fact there is less of a potential in nuken your speakers because the likelyhood of clipping in your PA is nearly eliminated at the same SPL. Often you will read the terms headroom or dynamic range used when perceptions of more powerfull amps are rated. These terms relate to clipping of your amp when it approaches its peak power levels which can severly damage your speakers.

    As far as bi-amping your speakers... you have effectively doubled your dynamic range and have almost eliminated the potential of clipping which will actually be better for your speakers at those same SPL's.

    I have experimented with biamping my center and fronts and for me I heard the benifit with my center the most.

    I figure the more power available the better and in my case I have 400W biamped driving my 400i and will never look back.

    My 800i's are ran in parallel with a vintage RTA8T and I really like what I hear. I have alot of control over my sweet spot. In this configuration my Outlaw is rated to 350W into 4 Ohms and I have never heard an indication of clipping. "IMHO the Outlaw is a BEAST and gives me everything I ask of it." Well worth the coin a paid.



    Looks like your on the same path as me about a year ago... Have fun because it is fun.

    HBomb
    ***WAREMTAE***
  • mangata572
    mangata572 Posts: 52
    edited February 2003
    THanks H. Rotel, Anthem, Outlaw, Sunfire, B&K, Adcom, etc. This will take lots of time and advice to deside. I just wonder if it's worth it with the RTi speakers.
  • HBombToo
    HBombToo Posts: 5,256
    edited February 2003
    Originally posted by mangata572
    I just wonder if it's worth it with the RTi speakers.

    ABSOLUTLY! IMO that is a great speaker line! I was amazed at how much my sound improved and my next upgrade will be to the 150. Enjoy those 150's because they are some bad ****'s!

    HBomb
    ***WAREMTAE***
  • Ron-P
    Ron-P Posts: 8,516
    edited February 2003
    Completely worth the upgrade.

    I have my center (CS400) and my mains (RT-55's) bi-amped with Adcom GFA-535's, stereo amps rated at 60wpc. I still use my Marantz SR5000 as the pre/pro. The upgrade to seperates was very, very noticable. Do it!


    Peace Out~:D
    If...
    Ron dislikes a film = go out and buy it.
    Ron loves a film = don't even rent.
  • faster100
    faster100 Posts: 6,124
    edited February 2003
    Originally posted by mangata572
    I just wonder if it's worth it with the RTi speakers.

    I wonder why people feel this way about $1,500 dollar speakers, They aren't all that cheap considering...

    The lsi line isn't best for all avenues either so i hear, The RTI line is only one level below the top line Polk carries, Right.. They are great speakers
    MY HT RIG:
    Sherwood p-965
    Sherwood sd871 dvd
    Rotel 1075 amp x5
    LSI15 mains
    LsiC center
    LSIfx surround backs
    Lsi7 side surrounds
    SVS pb12/plus2


    2 Channel Rig:

    nad 1020 Pre-amp
    Rotel 1080 stereo amp
    Polk sda 2B
    kenwood grunt Tuner
    realistic lab 450 TT
    Signal cable IC
  • mantis
    mantis Posts: 17,032
    edited February 2003
    I think it's a good question.
    I feel that way about the rt line.Seperates I feel needs better speakers to go along with them.Thats my opnion.
    The rti line works good with better receivers.Cheaper receivers,under a grand is where I would go exploring when looking for better sound.
    Upgrading to seperates, my question is why?What exactly are you looking for and what is it about what you own now thats not doing it for yeah?
    Dan
    My personal quest is to save to world of bad audio, one thread at a time.
  • Tour2ma
    Tour2ma Posts: 10,177
    edited February 2003
    Originally posted by mangata572
    Thanks H. Rotel, Anthem, Outlaw, Sunfire, B&K, Adcom, etc. This will take lots of time and advice to deside. I just wonder if it's worth it with the RTi speakers.
    Great middle line there mangata. Getting there is half the fun. But start heading towards the power ASAP. As Ron said, you'll notice a difference once you arrive.

    Years ago I took a giant leap with my 2 ch rig, from a Heathkit AA-15 (~50 wpc) to my beloved Carver M1.5t (350/600 wpc). The Yamaha's I was running at the time sang a whole new tune.

    Next you'll be asking, "New Polks or New AVP?"

    BTW, good first reply Hbomb. I despise speaker manf's capping their recommended amp power... min's fine, but max's? I believe that the max's lead to more bad amp decisions than we can ever count. I'll bet more speakers have been killed by clipping and high THD than by being overpowered. The only protection my "80 watt max" Yammies ever needed were my ears, which would have bleed before the Yammies blew.
    More later,
    Tour...
    Vox Copuli
    Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb

    "Death doesn't come with a Uhaul." - Dennis Gardner

    "It's easy to get lost in price vs performance vs ego vs illusion." - doro
    "There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD
  • brettw22
    brettw22 Posts: 7,621
    edited February 2003
    Originally posted by HBombToo
    I figure the more power available the better and in my case I have 400W biamped driving my 400i and will never look back.
    Originally posted by Tour2ma
    I despise speaker manf's capping their recommended amp power... min's fine, but max's? I believe that the max's lead to more bad amp decisions than we can ever count. I'll bet more speakers have been killed by clipping and high THD than by being overpowered.

    So y'all are saying that even though you provide virtually twice the recommended max power that you aren't risking killing the speaker? I realize that you're not going to really HEAR 400w(for HB's center) unless you have the thing turned up all the way, but why wouldn't the speaker blow especially if you're overpowering them? Just curious.......
    comment comment comment comment. bitchy.
  • HBombToo
    HBombToo Posts: 5,256
    edited February 2003
    Originally posted by brettw22


    So y'all are saying that even though you provide virtually twice the recommended max power that you aren't risking killing the speaker? I realize that you're not going to really HEAR 400w(for HB's center) unless you have the thing turned up all the way, but why wouldn't the speaker blow especially if you're overpowering them? Just curious.......

    Don't get me wrong here... I have the potential of melting the crossover... ;)

    :lol:

    I would never try to drive the speakers intentionally past their rated power but my ears start hurting at about 100 dB so I'm the protection circuit in this case. The statements I made were at the same SPL so really we are talking about the same power but greater headroom.

    HBomb

    HBomb
    ***WAREMTAE***
  • Tour2ma
    Tour2ma Posts: 10,177
    edited February 2003
    Hbomb… I've always thought it more likely that the woofer would go before the tweeters or crossover in an overpowered speaker, but we’re lock-step about the our ears being a speaker’s first line of defense.

    Brett,
    Think of it this way. An average Polk stereo rig is going to pump out around to 100 db at about 20 w of continuous amp power, well within the handling capability of any decent speaker. And 100 db is loud enough for OSHA to require signposts in your listening room that “hearing protection is required”. And at a speaker rating of 100w, the SPL will be ~107db. At this level an OSHA inspector would likely shut you down, or at minimum "cite you". This is why Hbomb and I say your ears will protect you and therefore your speakers.

    Let’s go back to the 100db, 20w example for a second. If you're bopping along at this level and a 0.25 second, 112-db crescendo comes along, the power requirement jumps to 320 w! At this demand a “safe”, 100wpc amp clips and distorts its **** off as it falls ~200 w short of the demand. But the 500wpc amp delivers the transient cleanly and easily, i.e., with low distortion. The clipping and distortion are FAR more likely to damage the speaker than the clean transient.

    If you want high power with a measure of added protection for your speakers, add an in-line fuse to their wiring. Polk, or other manufacturer, should be willing to supply you with the proper fuse for your model. Their recommendation should include amperage AND speed, i.e., fast/ normal/ slow- blow.

    I bought RS fuse holders for my Yammies years ago and never installed them. I never clipped my M1.5t into them, but I know they saw 300 to 400 w transients often during Symphonic play time, and they ate it up.

    Continuous vs. transient demands, and adequate clean power are the keys. To me this means high power...
    More later,
    Tour...
    Vox Copuli
    Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb

    "Death doesn't come with a Uhaul." - Dennis Gardner

    "It's easy to get lost in price vs performance vs ego vs illusion." - doro
    "There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD